1. Field of the Invention
This invention relates to apparatus for making needle felts for paper machines from a sliver which is applied at a bias angle to an endless backing web that is trained around deflecting rollers, which apparatus comprises a needle machine and a sliver feeder which is displaceable by a traversing drive across the working width of the needle machine.
2. Description of the Prior Art
From Austrian Patent Specification No. 375,101 it is known that endless needle felts for paper machines can be made in that a sliver is fed in a longitudinal direction by means of a sliver feeder to an endless backing consisting of a woven fabric and said feeder is reciprocated across the width of the backing so that juxtaposed sliver loops can be applied to the backing at a predetermined bias angle in two or more layers. Because the fibers of adjacent layers cross each other, any unbalance caused by one layer with respect to the direction of travel will be compensated so that a paper machine felt made in that process will have excellent running properties and strength values, particularly because the loops formed by the sliver are needled to the woven fabric backing by means of a needle machine having a working width which equals the width of the paper machine felt to be made. But the needling of the sliver loops to the backing woven fabric must be expected to result in a change of the width and length of the web which has been formed from the woven fabric backing and the sliver loops which have been needled to said backing so that the bias angle of the previously applied sliver loops will change relative to the bias angle of the loops to be applied and can no longer be applied by the sliver feeder to the previously and sliver loops in such a manner that adjacent edges of said loops will closely adjoin each other. The resulting deviation of adjacent longitudinal edges of juxtaposed sliver loops from a parallel course will obviously result in undesirable irregularities in the structure of the paper machine felt.